Journal of Zoo and Wildlife Medicine最新文献

A one-year-old female Eastern black-and-white Colobus (Colobus guereza) was evaluated after tangling its right forelimb in exhibit netting. Radiographs of the right forelimb revealed craniolateral luxation of the radial head and a complete transverse fracture of the proximal ulna, otherwise known as a type III Monteggia fracture. Open reduction was performed and a locking cuttable bone plate was placed to address the ulnar fracture. The reduced radial head was maintained by the placement of a Mini Tightrope Fixation System. Rapid return to normal activity was observed. Radiographs taken four weeks post-operatively showed healing of the fracture as well as appropriate articulation of the radial head. At three years post-operatively, the Colobus continued to demonstrate normal ambulation without evidence of growth disruption. This is the first documented report of this specific surgical technique and implant in an exotic species.

Hand-rearing protocols for nondomestic ungulates used for research, zoological parks, and reintroduction to the wild are evaluated on the basis of implementation practicality, gastrointestinal disturbances, survival to weaning, and growth rates compared with those of dam-raised individuals. Although species-specific protocols utilizing milk replacers formulated for nondomestic ungulates have been reported, no such protocols have been published for pronghorn (Antilocapra americana). Five pronghorn fawns were fed Day One 30/40 Black Tail Deer plus Lactobacillus acidophilus probiotics four times per day with Day One Ultra Boost (all products from Fox Valley Animal Nutrition, Inc, Huntley, IL 60142, USA) added at one feeding per day and weighed twice per week for up to the first 16 wk of life. All fawns survived beyond weaning and four out of five fawns experienced a combined total of seven bouts of diarrhea. Based on a linear mixed-effects model, the growth rate of pronghorn fawns was 178 g/d (SE, 14.8; 95% CI, 149-207). The observed growth rate was greater than or similar to that of individuals fed evaporated milk five times per day, a dam-raised singlet, and a singular set of dam-raised twins. Despite small sample sizes, this protocol shows promise as a method for hand-rearing pronghorn at growth rates comparable to those of dam-raised fawns.

Cortisol, and other glucocorticoids, are routinely used as markers of physiological stress in wildlife. Typically, stress activates the hypothalamic-pituitary-adrenal (HPA) axis, with adrenocorticotropic hormone (ACTH) signaling the adrenal glands to release cortisol. Nevertheless, recent anecdotes in captive Coquerel's sifakas (Propithecus coquereli), strepsirrhine primates that are difficult to maintain under human care, may challenge the assumption that physiological stress universally increases circulating cortisol. Here, the authors ask if low circulating cortisol and minimal response to adrenal stimulation might be hallmarks of outwardly healthy sifakas in captivity. Comparative ACTH stimulation or control tests were performed in 10 Coquerel's sifakas and six ring-tailed lemurs (Lemur catta) at the Duke Lemur Center (DLC). At baseline, sifakas had average cortisol concentrations of just 0.67 µg/dl, whereas those of ring-tailed lemurs averaged 12.53 µg/dl. Stressful pre-experiment procedures, including kenneling and handling, activated the HPA axis in ring-tailed lemurs, masking further cortisol release from ACTH administration; however, neither these procedures nor exogenous ACTH raised cortisol concentrations in sifakas. Additionally, cortisol in dozens of serum samples from DLC sifakas banked over 17 yr was assayed. Across samples, cortisol concentrations averaged just 0.49 µg/dl and did not vary by animal sex, age, or housing condition. Comparable samples from two individual sifakas in sepsis at the end of life (4.28 and 21.88 µg/dl) indicate that the assay does capture meaningful variation in cortisol in captive sifakas, although robust biological validation is needed. Currently there is a lack of comparative data from wild Coquerel's sifakas that might determine if these unusual endocrine patterns are characteristic of the species or a function of captivity. If the latter, chronic stress in captivity could lead to a downregulated HPA axis, with persistent hypocortisolism perhaps contributing to the Coquerel's sifaka's susceptibility to infection under human management.

Currently there are few antibacterial dosage regimens established to be safe and effective for sea turtles. Pharmacokinetic evaluation of antibiotics is an essential step in establishing accurate dosage guidelines for a particular species. Metronidazole is an antibiotic that is effective against anaerobic bacteria and some protozoa. For most anaerobic bacteria, the minimum inhibitory concentration (MIC) for metronidazole ranges from 0.25 to 4.0 µg/ml. The MIC values for some Clostridium species are up to 8 µg/ml, and for protozoal agents of trichomoniasis (MIC of 0.05 µg/ml), amebiasis, and giardiasis the MIC ranges from 1 to 50 µg/ml. The objective of this study was to determine the pharmacokinetic parameters after administration of metronidazole to aid in the establishment of species-specific dose guidelines in green (Chelonia mydas), loggerhead (Caretta caretta), and Kemp's ridley (Lepidochelys kempii) sea turtles. After administering metronidazole at a dose of 20 mg/kg orally and IV, the pharmacokinetics were very similar for these three species of sea turtles (n = 6 for each species). For both oral and IV routes of administration, plasma metronidazole concentrations were maintained above 8 µg/ml for approximately 24 h and above 4 µg/ml for approximately 48 h; however, plasma concentrations of 8 µg/ml were reached within 5 min only for the IV route, versus 8 h for the oral route.

Only limited data on concentrations of trace elements in the blood of avian species have been published. This information can play an important role in the conservation of endangered species and their protection from environmental pollutants and can also be clinically relevant in managed individuals. Some elements are essential for the health of the animals in human care, but little is known about expected concentrations for some of these elements. Therefore, 21 elements (silver, arsenic, gold, barium, cadmium, cobalt, chromium, copper, iron, iodine, mercury, magnesium, manganese, molybdenum, nickel, platinum, antimony, selenium, thallium, vanadium, and zinc) were measured by inductively coupled plasma mass spectrometry in lithium-heparinized plasma samples from Humboldt penguins (Spheniscus humboldti) from a single zoological collection in Germany (n = 39). The plasma concentrations of cadmium, nickel, platinum, antimony, and thallium were under the limit of detection in most of the analyzed samples. The results also showed that the females had significantly (P ≤ 0.05) higher concentrations of silver, barium, cobalt, chromium, iron, mercury, magnesium, vanadium, and zinc in their plasma in comparison with males. A correlation between the element plasma concentration and the age of the individuals could not be found. The differences in plasma concentrations of individual element between males and females could be due to hormonal influences on the metabolism. Further studies in different seasons and other age groups are needed in the future to investigate environmental and host effects in more detail and to understand physiological mechanisms responsible for observed differences.

American alligators (Alligator mississippiensis) are an important apex predator of semiaquatic habitats of the southern United States. Commercial alligator farming has grown in the last several decades, leading to a need to understand the health conditions that affect this species to ensure appropriate management and welfare. The aims of this study were 1) to establish and describe normative data including results of common ophthalmic diagnostic tests and conjunctival flora, 2) document ocular pathology in this population, and 3) assess the effect of topical rocuronium bromide and 10% phenylephrine for facilitating pharmacologic mydriasis. A total of 165 juvenile American alligators were evaluated in this study. Assessment included palpebral fissure length (PFL), intraocular pressure (IOP), strip meniscometry (SM), central corneal thickness (CCT), anterior segment examination, and bacterial and fungal culture sampling of the conjunctiva. Topical rocuronium bromide (RB) and 10% phenylephrine (PE) were applied to the right eye (OD) of eight individuals, and pupil diameter (PD) of both eyes measured at regular time intervals. Mean (±standard deviation [SD]) PFL was 10.55 ± 1.47 mm, IOP was 8.16 ± 1.48 mmHg, CCT was 150.06 ± 8.25 µm, and SM was 3.42 ± 2.07 mm/5 s. Culture results stress the importance of proper handling protocols in crocodilians given the high number of opportunistic pathogens isolated from the conjunctiva, as well as the first report of isolation of Lactococcus garvieae in this species. Acquired ophthalmic lesions, likely traumatic, were recorded and no congenital anomalies were observed. Topical administration of RB and PE resulted in a significant increase in nonilluminated pupil diameter (PD) starting at 20 min, and maximum dilation was achieved at 90 min. Fundic examination was achievable, and no adverse systemic effects were noted. This study contributes to a growing body of knowledge regarding ocular health of American alligators.

We describe a mortality event involving at least 44 adult American robins (Turdus migratorius) that were found dead on the morning of February 25, 2023 in a residential backyard in Natchitoches Parish, Louisiana. Five carcasses were submitted for diagnostic evaluation. All five robins were in good nutritional and feather condition with no external indicators of injury or illness. Grossly, kidneys were diffusely pale in all robins and 4/5 also had splenomegaly. Consistent histologic lesions included severe, multifocal to coalescing, renal tubular degeneration and necrosis with intraluminal, birefringent calcium oxalate crystals and calcified concretions. Toxicologic testing revealed a markedly elevated calcium concentration (10,000 parts per million) in a pooled kidney sample. Collectively, these findings support a diagnosis of ethylene glycol toxicosis. Ethylene glycol, an ingredient in antifreeze, is a hazardous toxicant in domestic and wild animals living in residential areas, although confirmed reports in songbirds are scarce. In the present case, the circumstances of ethylene glycol exposure are unknown but most likely anthropogenic in origin. Additionally, splenomegaly prompted molecular testing, which detected Plasmodium unalis in three robins and P. vaughani in one robin. Both Plasmodium spp. can infect a wide range of hosts, and although infections likely were subclinical, their detection raises awareness of their potential pathogenicity in wild birds. This mortality event underscores the need to recognize health risks posed by environmental contaminants and vector-borne pathogens to wildlife, and reinforces that wildlife, especially peridomestic species, can serve as sentinels for risks to domestic animal and human health.

In captivity, neotropical Seba's short-tailed bats (Carollia perspicillata) (Chiroptera: Phyllostomidae) reproduce readily, and contraception can constitute an opportunity to prevent uncontrolled reproduction, which can lead to overpopulation as well as inbreeding. The authors developed a safe and efficient work flow, anesthetic, and surgical castration protocol for the reproductive control of a captive population of more than 500 bats housed at the rainforest house at the Vienna Zoo, Austria. An anesthetic protocol using 0.003 mg medetomidine per bat (approximately 0.18 mg/kg) and 0.3 mg ketamine per bat (approximately 18 mg/kg) achieved surgical anesthesia in 323/328 bats, with the remaining five requiring supplementation with isoflurane. A single bat, which had a pre-existing underlying infection, died during anesthetic induction. Standard closed orchiectomy was performed on a total of 336 bats. The practicable and safe working protocol developed required three veterinarians and 3-4 assistants for the orchiectomy of this large group of captive bats. With the described work flow, the period for castration averaged 2.38 min/bat, resulting in managing 28.2 bats/h.

Crustaceans are housed in zoos and aquariums and have also gained importance in the private sector and food industry. Shell lesions are common and often attributed to bacterial infections. However, few controlled studies have been performed evaluating antibiotics in crustaceans. This study assessed the pharmacokinetics of a single dose of ceftazidime (22 mg/kg) given by IM or IV injection in wild-caught signal crayfish (Pacifastacus leniusculus). Pharmacokinetic parameters were calculated by noncompartmental analysis of sparse data. Maximum ceftazidime hemolymph concentration following IM administration was 124.6 ± 14.7 µg/mL and Tmax was 5 min, with 80% bioavailability. Following IV administration, the extrapolated maximum concentration of ceftazidime, (C [0]), was 581.4 µg/mL. Ceftazidime was last detected at 72 hr and 120 hr post IM and IV administration, respectively. Terminal half-life was 8.03 hr and 10.3 hr after IM and IV administration, respectively. Results suggest that both routes have the capacity to reach a maximum hemolymph concentration quickly in signal crayfish. Moreover, ceftazidime was maintained above a concentration of 4 µg/mL, a published minimal inhibitory concentration for Vibrio spp., for 24 hr for both IM and IV routes. Therefore, ceftazidime may be useful for infections with susceptible Vibrio spp. in signal crayfish.

The aye-aye (Daubentonia madagascariensis) is an unusual lemur with a small population in human care. Cardiac pathologies, but not normal size parameters, have been reported in this species. This study aimed to determine whether radiographic cardiac scaling systems commonly used to evaluate heart size in domestic mammals have potential clinical application in aye-ayes. Selected cardiac silhouette, vertebral, and intrathoracic skeletal dimensions were measured retrospectively on paired sets of orthogonal thoracic radiographs collected during health examinations of aye-ayes maintained at three British zoos. Measurements from 21 healthy aye-ayes (10 males, 11 females) of varying ages were used to calculate reference intervals (RI) with 90% confidence intervals for vertebral heart scale in both right lateral (VHS-RLat) and ventrodorsal (VHS-VD) projections, a modified VHS (VHS-Mod), thoracic inlet heart size (TIHS), and cardiothoracic ratio (CTR). VHS-VD (9.49 ± 0.29) was slightly higher than VHS-RLat (9.32 ± 0.33; P = 0.08) and had the lowest coefficient of variation of the scaling indices; TIHS was 4.89 ± 0.36, VHS-Mod was 11.07 ± 0.49, and CTR was 0.53 ± 0.05. Thoracic depth-to-width ratio of aye-ayes ranged between 0.75 and 0.91, equivalent to an intermediate thoracic morphology in dogs. No scaling indices differed significantly by sex, age group, or thoracic morphology; however, VHS-Mod and CTR were significantly correlated with bodyweight (P = 0.0022 and P = 0.041, respectively) and CTR with age (P = 0.02). Summed cardiac dimensions demonstrated a near-linear relationship with bodyweight and T4 vertebral length (both P < 0.05), but not thoracic inlet length (P = 0.12). Analysis of measurements by using serial radiographs from hand-reared animals indicated potential utility of RI in aye-ayes >0.4 yr. Overall, results suggest VHS-VD and VHS-RLat are preferred cardiac scaling indices in aye-ayes. These data will aid zoo clinicians in the evaluation of cardiac size and identification of cardiomegaly in this endangered primate.